A green roof in northern New Mexico is 2’ of dirt acting as the roof of a 100-year-old adobe building and the grasses, wildflowers and trees that naturally grow out of it.

These days a green roof is an engineered system of waterproofing, drainage, soil and plants that has environmental benefits that creates jobs.

Green roofs in urban areas keep temperatures down, reducing cooling costs, and serving as excellent storm water management systems. They support native wildlife in an area where there is little natural space. Some have food growing on them.

The green job sector is growing faster than any other. It doesn’t seem to care about this down economy! The green roof industry alone grew by 28.5% in 2010, a big increase from 16% in 2009.

The top U.S cities for green roof growth

Chicago

Washington DC

New York

Philadelphia

Norfolk, VA

Milwaukee, WI

Baltimore, MD

Atlanta

Seattle

These cities offer incentives and have regulations that recognize the environmental and employment benefits of green roofs.

What’s Involved in Building a Green Roof?

At the beginning of the construction process, an engineer is hired to analyze the building and the weight load of the projected garden. The roof is shored up if need be. Adequate support is designed into new construction. A consultant and the garden owner design the garden adhering to the engineer’s recommendations.

Photo: inspiration_seeker

A professional team is then called in to install the garden. They lay a waterproof barrier on the decking. This part is crucial to the success of the garden. Once it is installed, you don’t want to be tearing it up to address leaks! A root barrier is laid on top of that to keep roots from penetrating the waterproof barrier. Drainage in the form of gravel disperses water evenly. A particular soil mix is placed on top of the drainage, and plants are planted. Drip irrigation is optional, but a good idea for drought years. At the very least, plumbing and a spigot should be installed close by. Plants need to be watered heavily the first year to get them established.

Photo: kcxd

Types of roof gardens and green roofs

No garden is maintenance free. There are two types of roof gardens – extensive and intensive. An extensive roof garden consists of low-lying plants, such as succulents, grasses and moss in shallow soil. It only needs to be checked twice a year. If this is a residential garden, the homeowner may want to do the maintenance.

An intensive roof garden has deeper soil and more elaborate plants such as food crops, ornamental shrubs and trees. It is the kind of garden you relax or entertain in, so it may have paths and sitting areas. These gardens need regular maintenance like any professionally landscaped yard.

Both scenarios include checking to see if the components are in good shape, weeding, removing and replacing dead or dying plants, fertilizing, pruning, checking for and resolving pest issues, and keeping the gutters and drainage areas clean. This is a regular landscaping job. I was a landscaper for over 20 years, and I’m thinking I’d like to work on a roof garden!

Green jobs in commercial roof gardening and green roofing

So far, the jobs and careers necessary for a green roof or roof garden are:

Engineering

Designing

Installing

Irrigation

Maintenance

Then there are the manufacturers and suppliers of the various components, as well as plant nurseries. Some nurseries specialize in green roof plants!

Since this is such a fast growing industry, it seems like it would be a great way to find a green job or career or to start a green business.

Nan Fischer has been living and building green for over 35 years. Nan’s emphasis on the BuildDirect blog is about how to make your dollar stretch further, while also moving toward a more sustainable lifestyle, as well as upcoming and existing technology to help us live in an ecologically-friendly way. Nan also authors posts on the website of her seed business, sweetly seeds.